Door openings to be opened and closed by side doors are formed in side sections of ordinary vehicles, such as passenger automobiles. Generally, the lower edge of such a door opening is set at a low height to allow a passenger to get in and out of the vehicle with ease. The lower edge of the door opening is defined, for example, by the upper surface of a side sill. A construction of a side sill is disclosed, for example, in Patent Literature 1. Further, a technique for covering the lower edge of a door opening with a step garnish is disclosed, for example, in Patent Literature 2.
A vehicle body disclosed in Patent Literature 1 is constructed of plate materials differing among various portions of the vehicle body and such different plate materials are joined together, in order to achieve an enhanced quality and reduced weight. For example, lower end portions of a center pillar and a rear pillar are lapped over and joined to a side sill. Namely, a part of the side sill is constructed by the plate materials, forming the center pillar and the rear pillar, being lapped over the plate material forming the side sill. Thus, the side sill has a stepped joint section where the plate materials are lapped over and joined to each other.
Generally, a seal member is provided on the peripheral edge of the vehicle door. With the door in a closed position, the seal member contacts and seals an outer side surface, located outward in a vehicle width direction, of the side sill. If the side sill has a joint section as in the vehicle body disclosed in Patent Literature 1, the joint section would adversely influence the sealing performance of the sealing member. Further, in the case where the lower edge of the door opening is defined by the upper surface of the side sill and if the joint section is exposed on the upper surface of the side sill, the joint section is undesirably visible from outside. Therefore, a further improvement has to be made in order to enhance the outer appearance of the vehicle body.
Further, a vehicle body disclosed in Patent Literature 2 has a step plate (step garnish) provided on the lower edge of the door opening. The step plate is an aluminum plate constructed to allow a foot (or feet) of a passenger to be placed thereon and covered along its outer periphery with a decorative resin cover. Such a decorative resin cover can enhance the outer appearance of the step plate.
Further, merely combining the technique disclosed in Patent Literature 2 with the technique disclosed in Patent Literature 1 cannot enhance the sealing performance provided by the seal member in the joint section of the side sill, nor can it enhance the outer appearance of the lower edge of the door opening.